1. Field of the Invention
The present invention relates to an electronic device and a computer program product that have, as operation modes, a normal mode and an energy-saving mode reduced in power consumption as compared with that of the normal mode.
2. Description of the Related Art
In a conventional image forming apparatus like a multifunction printer (MFP) that implements a plurality of functions such as a scanner function, a printer function, a copying function, and a facsimile function in a single housing, the power consumption in a standby state and others is reduced to achieve energy conservation. Furthermore, monitoring the status of the image forming apparatus is performed conventionally by remote management that uses communication.
As the communication applicable for the remote management of an image forming apparatus, known is a communication method that uses Transmission Control Protocol/Internet Protocol (TCP/IP) as a communication protocol. As one example, by connecting an image forming apparatus and a management device remotely located with respect to the image forming apparatus through a network such as a local area network (LAN), the communication between the image forming apparatus and the management device is performed using the TCP/IP. A given command and others is then transmitted from the management device to the image forming apparatus, and a response of the image forming apparatus to the transmitted command is received by the management device, whereby monitoring of the status of the image forming apparatus by remote operation can be implemented.
In an image forming apparatus, a technique in which TCP/IP processing is performed in the kernel of an operating system (OS) is already known. Furthermore, there is a known technique in which TCP/IP processing is sub-systematized (chipped) in the kernel of an OS and the power is supplied to the sub-system even when a main system is in a power-off state (an energy-saving state). In this case, a packet transmitted from the outside through a network is detected by the sub-system, and the sub-system controls the power to the main system so as to return the main system to a normal state from the energy-saving state.
FIG. 8 illustrates an example of a configuration of an image forming apparatus 400 in conventional technology. The image forming apparatus 400 is connected with a controller 430, a sub-system 440, and a power supply unit (PSU) 470. The PSU 470 supplies the power to the controller 430 and the sub-system 440 in accordance with the control of a power controller 445, which will be described later.
The controller 430 includes a main central processing unit (CPU) 415, a synchronous dynamic random-access memory (SDRAM) 411, a flash memory 412, a hard disk drive (HDD) 413, a remote management system memory 417, and a peripheral component interconnect bus (PCI) 448, and the foregoing are connected to an application specific integrated circuit (ASIC) 416 to communicate with one another.
Likewise, connected to the ASIC 416 are an operation panel 414, an FCU 421, a plotter/scanner engine unit 424, and data I/Fs 422 and 423 each corresponding to, for example, universal serial bus (USB) and Institute of Electrical and Electronics Engineers (IEEE) 1394. The FCU 421 performs facsimile communication in accordance with G3 standard or G4 standard. The plotter/scanner engine unit 424 performs a printer function and a scanner function. A peripheral device 425 is, for example, an automatic document feeder (ADF) and is used, in the housing of the image forming apparatus 400, being attached to a printer/scanner portion. The ASIC 416 provides sharing of the respective units connected that are objects of the control of the main CPU 415, and mediates data transfer performed among the respective units.
The main CPU 415 controls the operation of the respective units connected to the ASIC 416 in accordance with a program and others stored in advance in the flash memory 412 or the HDD 413 using the SDRAM 411 as a work memory. For example, the main CPU 415 controls the FCU 421 and the plotter/scanner engine unit 424, in response to user operation performed on the operation panel 414, to perform functions such as facsimile communication, printing, and copying.
The PCI 448 is connected with a modem 401 that performs communication through a public telephone network 500. The remote operation of the image forming apparatus 400 through the public telephone network 500 is performed by the communication with the modem 401 using the remote management system memory 417.
The sub-system 440 includes a sub-CPU 441, a random access memory (RAM) 442, a read only memory (ROM) 443, a remote management system memory 444, the power controller 445, and a PCI 446, and the foregoing are connected to communicate with one another by an interface ASIC 447. The interface ASIC 447 provides sharing of the respective units connected that are objects of the control of the sub-CPU 441, and mediates data transfer performed among the respective units.
The sub-CPU 441 controls the operation of the respective units connected to the interface ASIC 447 in accordance with a program stored in advance in the ROM 443 using the RAM 442 as a work memory. The power controller 445 controls the operation of the PSU 470. Furthermore, a network interface card (NIC) 402 that controls connection to a network such as a local area network (LAN) and the Internet is connected to the PCI 446.
In the image forming apparatus 400 thus configured, when the operation of the image forming apparatus 400 is in an energy-saving mode, under the control of the power controller 445, for example, the supply of power to the controller 430 is set to off and the power is supplied only to the sub-system 440. During the energy-saving mode, when a packet transmitted to the image forming apparatus 400 through the network is received by the NIC 402, the sub-CPU 441 is notified of that via the PCI 446 and the interface ASIC 447. The sub-CPU 441 then, in response to the notice, controls the power controller 445 to turn on the supply of power to the controller 430.
In the image forming apparatus 400 in conventional technology illustrated in FIG. 8, contemplated is only a situation in which a packet is received from an external management device. Now, considered is a remote management system that performs dial-up communication with a management device by the modem 401 using the TCP/IP and Point-to-Point Protocol (PPP) through the public telephone network 500. In the remote management system, PPP processing is performed by the kernel of the OS in the managed functions of the image forming apparatus 400. Therefore, any of the following restrictions arise.
Firstly, in order to respond to an incoming call from the external management device and to perform dial-up communication as needed, the power to the controller 430 must always be set to on. Secondly, if the operation mode of the image forming apparatus 400 is in the energy-saving mode and thus the power to the controller 430 is set to off, the image forming apparatus 400 cannot respond to an incoming call from the external management device.
In this regard, Japanese Patent Application Laid-open No. 2000-295386 discloses a device with an energy-saving mode that temporarily changes a return condition by confirmation control so as not to return to a normal mode from the energy-saving mode depending on a signal transmitted from an ISDN network. In accordance with Japanese Patent Application Laid-open No. 2000-295386, by the confirmation control of incoming mail during the energy-saving mode, unnecessarily returning to the normal mode is prevented, whereby an energy-saving effect by the energy-saving function can be achieved effectively.
Furthermore, there has been a proposed technique in which communication from the outside is detected during an energy-saving mode and the operation modes are automatically returned to a normal mode from the energy-saving mode when the detected communication is from a prescribed device.
Meanwhile, in a device having an energy-saving mode as in the foregoing, the change in operation mode from the normal mode to the energy-saving mode is often performed automatically corresponding to the presence of a request to the device from the outside such as user operation. More specifically, the length of time in which user operation is not performed in the normal mode is measured, and when the measured time comes to a given length of time, the operation mode is automatically changed to the energy-saving mode.
The same applies when the operation mode is automatically returned to the normal mode from the energy-saving mode in response to the request made from the external management device and others through the communication. In this case, conventionally, the operation mode is not changed to the energy-saving mode unless a given time is passed from the time the operation mode is returned to the normal mode, and thus it takes time until the operation mode is returned to the energy-saving mode.
Particularly, because the communication with the external device occurs at a timing not intended by the user of the device, an ideal energy-saving effect may not be achieved.
Therefore, there is a need for an electronic device capable of enhancing the energy-saving effect, when returning from the energy-saving mode that is caused by the communication from the external device.